Abstract

Electron scattering mechanisms in copper lines were investigated to understand the extendibility of copperinterconnects when linewidth or thickness is less than the mean free path. Electron-beam lithography and a dual hard mask were used to produce interconnects with linewidths between 25 and 45 nm. Electron backscatter diffraction characterized grain structure. Temperature dependence of the line resistance determined resistivity, which was consistent with existing models for completely diffused surface scattering and line-edge roughness, with little contribution from grain boundaryscattering. A simple analytical model was developed that describes resistivity from diffuse surface scattering and line-edge roughness.

Received 10 September 2009Accepted 21 December 2009Published online 29 January 2010

Acknowledgments:

Portions of this work were performed at the Molecular Foundry, Lawrence Berkeley National Laboratory, which is supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Portions of this work were supported by the NIST Office of Microelectronics Programs under Project No. 2004-012.